CA2764774A1 - Method for making a metal part including a fibrous annular reinforcement - Google Patents

Abstract

Reinforcement of a metal part axisymmetric annulus by inclusion of a winding composite material. According to the invention, a metal blank (11) of the part is produced, there is created a cavity (14) opening on one side coaxial interior thereof and having a right cross section of axial length decreasing from the inside to the outside, we wraps a reinforcing wire (21) in the cavity, closes this cavity, we submit the whole to a hot isostatic pressing and one factory roughing to get the final piece.

Description

Process for manufacturing a metal part incorporating a fibrous annular reinforcement The invention relates to a metal part having a annular portion including a fibrous coaxial annular reinforcement, in the form of a coil of composite material enclosed in a matrix metallic. The invention relates more particularly to the manufacture of a such a piece with improved strength. It also concerns a metal part enclosing such a coaxial annular reinforcement.
It is known to reduce the mass of a metal part annular while ensuring a very high tensile strength or tangential compression, by incorporating fibers of material composite such as ceramic in the metal mass.
The ceramic is, for example, silicon carbide wire which has resistance to traction or compression greater than that of a metal, like titanium for example.
To obtain such a part, it is possible to perform a winding of wire of ceramic coated with metal inside a blank of the room. By For example, document FR 2 886 290 proposes winding directly on a part of the blank forming the winding mandrel. he this is an "external" winding of the most classic. More precisely, this part has two shoulders. The most internal shoulder radially forms a lateral bearing surface for the winding. The part adjacent cylindrical shape forms the base surface on which the winding. This one has a rectangular shape in cross section right. After winding, complete the blank with metal parts complementary, in particular an outer ring and a lateral cover having a pin coming into contact with the winding. This set is then subjected to a hot isostatic compression step during of which the lid, in particular, is deformed so that the winding is compressed by the tenon. The compression operation isostatic hot is known per se; it consists of placing the whole aforementioned in a box and to submit this set, for several hours, at a high pressure of the order of 1000 bar and at a temperature of around 1000 C. After this operation, the piece, all in one piece,

2 is machined to the desired shape and dimensions. Generally, different parts of the blank and the sheathing of the ceramic wire are same metal so that the finished piece is provided with an insert composite wound, embedded in a homogeneous metal matrix.
The area reinforced by the winding has a cross section generally rectangular right. To lighten the room and increase the tensile strength / compression in the tangential sense it is desirable that this zone reinforced, surrounded by parts exclusively metal, occupies as large a volume as possible.
This insert arrangement of rectangular cross-section may not not be completely satisfactory following the direction of the efforts that are applied to the piece. While fiber resistance is excellent tangential to both traction and compression, it is less to that of pure metal when efforts are applied in one direction transverse to the fibers. As examples, this is particularly the case when the annular piece thus manufactured is a rotating part provided with blades, such as a turbine disk, especially for a turbojet engine airline. Another piece subjected to transverse forces is the "rotating sleeve" connected to jacks in a landing gear mechanism.
With a part with a cross section winding Rectangular right, breaks are possible in the outside of the reinforced zone.
The basic idea of the invention is to establish a "zone of progressivity "in pure metal in this outer radial region, laterally between the periphery and the area where the turns are located. This leads, according to the invention, to conform the winding so that it has a right cross section of axial length decreasing radially to the outside at least in an outer radial zone of the axisymmetric part.
cudgel.
For example, a coiled portion having a cross section trapezoidal or triangle-shaped at least in its radially more external is likely to answer the problem data.
A half-wave shape can also be considered provided that the proportion of pure metal increases radially towards the outside of the room, all things equal otherwise.

WO 2010/14629

3 PCT / FR2010 / 051179 Another difficulty is then to make the part because the winding "external" as described above is difficult to envision. The invention also proposes a new approach to winding, called "internal winding".
More specifically, the invention relates to a manufacturing process an axisymmetric annular metal part reinforced by inclusion in it a coaxial annular reinforcement in the form of a coil in composite material, characterized in that it comprises the steps of at.
developing an annular metal blank of said part, - practice or complete a cavity opening on one side coaxial interior of said blank and having a section transverse right of axial length decreasing radially towards outside on at least part of its height, - winding a reinforcing thread in said cavity so as to fill substantially all the space thereof by a coil, closing said cavity by a metal wall element, - submit the set to a compression process hot isostatic, and machining said blank to obtain the final geometry of said room.
"Right cross section" means a section in a plane containing the axis of the axisymmetric part considered, plus precisely the axis of the sketch in the definition above.
According to an advantageous characteristic, the reinforcing thread is composed of a ceramic core, sheathed in metal.
The shape of the winding thus obtained, that is to say, in fine, the shape of the zone provided with ceramic fibers makes it possible to reserve radially out of said area and on either side thereof larger quantities of pure metal (titanium for example) allowing an effort essentially radial to "progressively" transfer into the fibers following directions turning it into more and more oriented effort tangentially.
The coil can be stabilized during its formation by welds joining certain turns together by their metal sheath, To proceed with the so-called "internal" winding, winding is initiated reinforcing wire by fixing one end of it to the bottom of the cavity and

4 the winding is continued by rotating the blank about its axis while feeding the wire at a controlled speed with respect to the speed of rotation of the blank.
Advantageously, the feeding speed of the wire is such that urges said blank in the direction of rotation thereof.
The invention will be better understood and other advantages of this will appear more clearly in the light of the following description illustrating a method of manufacturing an annular metal part axisymmetric reinforced by a coaxial winding, given only to As examples and with reference to the accompanying drawings, in which - Figures 1, 2, 3A and 4 to 6 illustrate with sectional views crosswise right the different stages of the manufacturing process of a axisymmetric annular metal part reinforced by winding a wire reinforcement;
FIG. 3B is a partial perspective view illustrating the phase of Figure 3A; and - Figure 7 shows the part thus obtained.
Referring to the drawings, a method will be described making it possible to produce an annular piece such as a rotor disk, from a metal blank 11, for example titanium, itself annular and axisymmetric, here rectangular rectangular cross section, as shown in FIG. 1. The axis of revolution of the blank is referenced X.
Of course, this section can have a different shape in function of the geometry of the final piece that one wishes to obtain.
The blank has a coaxial inner face 12, here cylindrical.
It is both a question of lightening the final piece while conferring on it increased mechanical strength.
After developing such a draft, the next step (Figure 2) consists in practicing, in the mass of the blank, for example by machining, a cavity 14 opening (opening) on said inner face coaxial 12. For example, it is possible to rotate the blank about the X axis and introducing a cutting tool through the accessible central portion of said draft. Material is removed until an annular cavity is obtained opening on said coaxial inner face of the blank. Note we can start from an already hollow blank, the machining operation simply to complete the cavity to give it shape and shape.
desired dimensions.
According to an important characteristic, the cavity 14 presents a

5 right cross section of axial length decreasing radially towards outside on at least part of its height. In the example, the cavity a (in a straight cross section and following a direction radial from inside to outside) an extended rectangular shape by a trapezoidal shape 16. This second part of the cavity could have a triangular shape or any other shape whose axial length (along the X axis) decreases from the inside to the outside.
This results in a reserve of pure metal in the lateral zones 17, 18 indicated in dotted line, compared to what would be obtained if the cavity had a rectangular cross section.
The next step is to wind a reinforcement wire in situ 21, here ceramic (silicon carbide) coated with metal. The metal is here titanium, that is to say the same metal as that which constitutes the blank.
This operation, illustrated in FIG. 3A, is carried out by introducing the wire by opening the cavity and depositing it from the cylindrical bottom 23 of the cavity by adjacent turns then by successive layers of turns to fill the entire space of the cavity, by a coil of joined turns 25.
For winding, this can be done. We feed the wire via a rigid tubular guide 27 movable in a controlled manner parallel to the X axis (to form a layer) and radially indented (to elaborate the following successive layers). Guide 27 is oriented as represented in FIGS. 3A and 3B, that is to say that its end 27A
a small angle to the circumferential winding direction turns.
The winding of the wire 21 is initiated by fixing (by welding) a end of it to the cylindrical bottom wall 23 of the cavity, near one end thereof and the blank 11 is rotated around its X axis, and feeding the wire at a controlled speed compared to the rotation speed of the blank. We can for example adjust in the speed at which the wire 21 is brought, so that this speed is always substantially equal to the winding speed,

6 given the speed of rotation of the blank and the diameter of the layer of turns during winding.
We can also make sure that the feed speed of the wire or that it solicits the roughing in the direction of rotation thereof. By for example, the wire 21 can be pushed inside the guide 27 by a motor rotary roller drive system (not shown) with possibility of longitudinal sliding so that said thread is lightly compression between its exit from guide 27 and the point where it takes its place in the winding. We can even consider that the blank 11 is mounted in free rotation and that it is the solicitation exercised on the wire itself which drives it in rotation during winding.
To avoid overflowing, the turns are stabilized at given winding intervals, by weld points or lines joining the metal sheaths of some turns.
In a manner known per se, the weld can be a weld electric or by induction, under vacuum or in a neutral atmosphere of argon.
A welding process as described in FR 2 886 290 can be set implemented.
The following operation, FIG. 4, consists in closing the cavity 14 filled by the coil 25. For example, it implements a wall annular cylindrical metal 30, here in titanium, next to the opening of the cavity. This wall here has the same length as the axial length of the opening so that during hot isostatic compression she may deform radially outward penetrate the cavity, compacting the winding itself. We can size the cylindrical annular wall 30 by ensuring that its diameter is slightly greater than that of the central opening of the blank but bearing this annular wall at low temperature (by plunging it into liquid nitrogen for example) before putting it in place. So even before the start of the hot isostatic pressing operation, the wall annulus 30 engages the cavity by beginning to compact the winding.
Advantageously, the closure of said cavity comprises its evacuation with hermetic closure by a metal foil 32 welded. This metal sheet is welded on both sides of

7 the opening of the cavity, before the isostatic compression operation to hot.
The isostatic compression operation is then carried out at hot itself, consisting, for example, of placing the blank, modified as shown in Figure 4, in a box for several hours by raising the pressure to 1000 bar and the temperature to 1000 C, about.
The result is shown in Figure 5. We see that the wall annulus 30 is engaged in the cavity, driving the metal foil 32. The whole is now a single block with a large part of the volume occupied by a coil of high-strength ceramic wire, embedded in a metal matrix resulting from the fusion of the sheath metallic wire used during winding.
We then proceed to a series of machining operations (FIG.
for purpose, from the rough transformed by the compression operation isostatic hot to define the contour 35 of the desired part (shown dotted line in Figure 6). The final piece 36 of FIG.
external lateral zones (17a, 18a) purely metallic, allowing to increase the transverse mechanical resistance of the part and to limit locally stiffness jumps favoring breaks. These areas called "progressivity" have the effect of making efforts gradually, by shearing, in the fibrous reinforcement (the winding) to convert the forces into circumferential traction / compression for which the resistance of the wound area is optimal.

Claims (6)

1. Method of manufacturing an annular metal part axisymmetric reinforced by inclusion in it of a ring reinforcement coaxial material in the form of a composite material coil, comprising the steps of:
- developing an annular metal blank (11) of said room, - practice or complete a cavity (14) opening on one side coaxial interior of said blank and having a section transverse right of axial length decreasing radially towards outside on at least part of its height, - winding a reinforcing thread (21) in said cavity so as to substantially filling the entire space thereof with a coil, characterized in that it further comprises the steps of:
- Close said cavity by setting up a cylindrical wall metal (30) facing the opening of said cavity, then, - submit the set to a compression process hot isostatic, and machining said blank to obtain the final geometry of said room. 2. Method according to claim 1, characterized in that said reinforcing thread (21) is composed of a core of composite material such that ceramics, sheathed in metal and that stabilizes the coil in training course by welds joining some turns between they by their metal sheath. 3. Method according to claim 1 or 2, characterized in that initiates winding of the reinforcing wire by attaching one end thereof to the bottom (23) of the cavity and that the winding is continued by turn said blank about its axis (X) by feeding the wire to a controlled speed with respect to the rotation speed of the blank. 4. Method according to claim 3, characterized in that the feeding speed of the wire (21) is such that it solicits said blank in the direction of rotation of the latter. 5. Method according to one of the preceding claims, characterized in accordance with said open cavity so as to give it a cross-section at least partly triangular or trapezoidal (16), at least in the outermost radial portion thereof. 6. Method according to one of the preceding claims, characterized in that the closure of said cavity comprises its evacuation with hermetic closure by a metal sheet (32) welded from and other of the opening of said cavity, before the compression operation isostatic hot.